body {
    max-width: 540px;
    min-width: 320px;
    margin: 0 auto;
    font: normal 14px/1.5 Tahoma, "Lucida Grande", Verdana, "Microsoft Yahei", STXihei, hei;
    color: #000;
    background: #f2f2f2;
    overflow-x: hidden;
    -webkit-tap-highlight-color: transparent;
}
ul {
    list-style: none;
    margin: 0;
    padding: 0;
}

a {
    text-decoration: none;
    color: #222;
}

div {
    box-sizing: border-box;
}
/* 导航栏位置 */
.search{
    display: flex;
    /* 固定定位跟父级没有关系 它以屏幕为准 */
   position: fixed;
   top: 0;
   left: 50%;
   transform: translateX(-50%);
   width: 100%;
   height: 44px;
   min-width: 310px;
   max-width: 540px;
   background-color: pink;
}
.search-box{

    margin-top: 6px;
    display: flex;
    width: 472px;
    height: 32px;
    border: 2px solid blueviolet;
    border-radius: 22px;
    /* justify-content: center; */
    align-items: center;
    flex: 1;
    box-shadow:3px 3px 3px rgba(0, 0, 0, 0.3) ;
}
.search-box i{
    display: block;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    margin-left: 5px;
    background-color: white;
}
.search-box input{
    outline: none;
    border: none;
    width: 200px;
    margin-left: 5px;
    background-color: pink;
}
.search a{
    width: 32px;
    height: 32px;
    margin:6px 0 0 12px;
    align-items: center;
    line-height: 32px;

}
/* 头部位置 */
.nav{
    display: flex;
    margin-top: 44px;
    /* padding-top: 44px; */
    height: 184px;
    background-color: blue;
    flex-wrap: wrap;
    
}
.nav li{
    background-color: brown;
    flex: 1;
    display: flex;
    flex-direction: column;

}
.nav li a{
    flex: 1;
    display: block;
    height: 60px;
    background: burlywood;
}

/* banner */
.banner {
    margin-top: 10px;
    height: 148px;
    background: cornflowerblue;
    display: flex;
    justify-content: space-between;
}
.banner-l,.banner-r{
    width: 254px;
    min-width: 20px;
    max-width: 260px;
    background: darkorange;
}